Added plugin autoinsert

README.md

@@ -10,6 +10,7 @@ to a something other than a raw file it should be marked with an asterisk.*
 
 Plugin | Description
 -------|-----------------------------------------
+[`autoinsert`](plugins/autoinsert.lua?raw=1) | Automatically inserts closing brackets and quotes
 [`autowrap`](plugins/autowrap.lua?raw=1) | Automatically hardwraps lines when typing
 [`bigclock`](plugins/bigclock.lua?raw=1) | Shows the current time and date in a view with large text *([screenshot](https://user-images.githubusercontent.com/3920290/82752891-3318df00-9db9-11ea-803f-261d80d5cf53.png))*
 [`bracketmatch`](plugins/bracketmatch.lua?raw=1) | Underlines matching pair for bracket under the caret *([screenshot](https://user-images.githubusercontent.com/3920290/80132745-0c863f00-8594-11ea-8875-c455c6fd7eae.png))*

plugins/autoinsert.lua

@@ -0,0 +1,75 @@
+local core = require "core"
+local config = require "core.config"
+local DocView = require "core.docview"
+local command = require "core.command"
+local keymap = require "core.keymap"
+
+
+config.autoinsert_map = {
+  ["["] = "]",
+  ["{"] = "}",
+  ["("] = ")",
+  ['"'] = '"',
+}
+
+
+local function is_closer(chr)
+  for _, v in pairs(config.autoinsert_map) do
+    if v == chr then
+      return true
+    end
+  end
+end
+
+
+local on_text_input = DocView.on_text_input
+
+function DocView:on_text_input(text)
+  local mapping = config.autoinsert_map[text]
+
+  -- prevents plugin from operating on `CommandView`
+  if getmetatable(self) ~= DocView then
+    return on_text_input(self, text)
+  end
+
+  -- wrap selection if we have a selection
+  if mapping and self.doc:has_selection() then
+    local l1, c1, l2, c2, swap = self.doc:get_selection(true)
+    self.doc:insert(l2, c2, mapping)
+    self.doc:insert(l1, c1, text)
+    self.doc:set_selection(l1, c1, l2, c2 + 2, swap)
+    return
+  end
+
+  -- skip inserting closing text
+  local chr = self.doc:get_char(self.doc:get_selection())
+  if text == chr and is_closer(chr) then
+    self.doc:move_to(1)
+    return
+  end
+
+  -- auto insert closing bracket
+  if mapping and (chr:find("%s") or is_closer(chr) and chr ~= '"') then
+    on_text_input(self, text)
+    on_text_input(self, mapping)
+    self.doc:move_to(-1)
+    return
+  end
+
+  on_text_input(self, text)
+end
+
+
+command.add("core.docview", {
+  ["autoinsert:backspace"] = function()
+    local doc = core.active_view.doc
+    local l, c = doc:get_selection()
+    local chr = doc:get_char(l, c)
+    if config.autoinsert_map[doc:get_char(l, c - 1)] and is_closer(chr) then
+      doc:delete_to(1)
+    end
+    command.perform "doc:backspace"
+  end,
+})
+
+keymap.add { ["backspace"] = "autoinsert:backspace" }